Photographic shutter

ABSTRACT

A photographic shutter having one set of blades, pivoted for fanwise movement on a common pivot, for opening the exposure aperture, and a second set of blades, also pivoted for fanwise movement, for closing the exposure aperture. Each set of blades is operated by its own operating lever, and both operating levers are driven by the same driving element which, in turn, is driven by a main driving member or master member.

United States Patent Weiss [54] PHOTOGRAPPHC SHU'I'IER [72] Inventor:Hugo Weiss, Atterseestrasse 6, 8

Munich 60, Germany 22 Filed: May 13, 1970 [21] Appl.No.:36,897-

[30] Foreign Application Priority Data May 28, 1969 Germany ..P 19 27158.0

[52] US. CL ..95/60 [51] Int. Cl. ..G03b 9/20 [58] Field of Search"95/53 R, 58, 59, 6O

[56] References Cited UNITED STATES PATENTS Loseries ..95/60 Aug. 15,1972 3,479,946 11/1969 Bohm ..95/60 Primary Examiner-Samuel S. MatthewsAssistant Examiner-Russell E. Adams, .lr

Att0rneyCharles Shepard and Stonebraker & Shepard [S7] ABSTRACT Aphotographic shutter having one set of blades, pivoted for fanwisemovement on a common-pivot, for opening the exposure aperture, and asecond set of blades, also pivoted for fanwise movement. for closing theexposure aperture. Each set of blades is operated by its own operatinglever, and both operating levers are driven by the same driving elementwhich, in turn,

is driven by a main driving member or master member.

7 Claims, 6 Drawing Figures PATENTEUAUB 15 1972 3. 683. 778

SHEET 3 OF 3 PHOTOGRAPHIC SHUTTER BACKGROUND OF THE INVENTION In most ofthe modern and currently used photographic shutters, there are severalblades, each pivoted on its own individual pivot, usually mounted in anannular casing or housing and operated by a blade ring which rotatesconcentrically with the exposure aperture at the center of the housing.As distinguished from this usual construction, the present constructionprovides a set or series of blades mounted for fanwise swinging on asingle or common pivot, from a closed position extending across theexposure aperture to an open position allowing light to pass through theexposure aperture, and a second set of blades similarly mounted forfanwise swinging movement on a common pivot, from an open positionpermitting passage of light through the exposure aperture (when it hasbeen uncovered by opening of the first set of blades) to a closedposition obstructing passage of light. The second set of blades may bemounted to swing on the same pivot as that of the first set of blades.

When an exposure is to be made, a main driving member or master membermoves a driving element, which may be in the form of a rotatable ring,from one extreme or end position to another extreme or end position.This movement of the driving element'serves, through intermediatemembers such as levers, to move the previously closed set of blades froma fanned out position to a collapsed position, thereby opening theexposure aperture and initiating the exposure, and subsequently movesthe other set of blades from a collapsed position to a fanned outposition, thereby closing the exposure aperture and terminating theexposure. For the next exposure, the procedure is reversed, the secondset of blades which constituted the closing set of blades in theprevious exposure now becoming the opening set of blades, while theother set which previously constituted the opening set in the previousexposure, now constitutes the closing set of blades.

It is an object of the present invention to provide a shutter which hasa comparatively large exposure aperture or light aperture in comparisonto the external dimensions of the shutter housing.

Another object is the provision of a shutter in which all of the movableparts or elements move in a single direction only, during the making ofa single exposure, avoiding any reversal of movement and therebyfacilitating the making of exposures with very short exposure times orhigh speed.

Still another object is the provision of a shutter so designed as tohave relatively few parts, of simple construction, easy and inexpensiveto manufacture and to assemble, the parts being so shaped that they maybe accommodated within a comparatively small casing or housing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front face view of ashutter according to a preferred embodiment of the invention, with thefront cover plate removed to show the interior construction,illustrating the first set of shutter blades in fanned out positionextending across and closing the exposure aperture, the second set ofshutter blades and various other parts being omitted for the sake ofclarity;

FIG. 2 is a similar view with the first set of shutter blades and otherparts omitted, and with the second set of shutter blades shown incollapsed or folded position so as not to obstruct the exposureaperture;

FIG. 3 is a similar view showing the parts in an intermediate positionduring the making of an exposure, with both sets of blades open so thatlight may pass through the exposure aperture;

- FIG. 4 is a similar view showing the parts at the conclusion of anexposure cycle, with the first set of blades now collapsed to anon-obstructing position and with the second set of blades fanned out toclose the aperture;

FIG. 5 is a schematic perspective view of the main driving member ormaster member and certain associated parts including the tensioning orcocking parts; and

FIG. 6 is an axial cross section taken diametrically through the shutterapproximately on the line Vl-Vl of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment, theshutter has a casing or housing of the usual annular form, indicated ingeneral at 10 and having a central exposure aperture or light-admittingaperture 10a. Fixed in the housing is a bearing pin or pivot pin 12which serves as the common pivotal axis for all of the blades of twoseparate fantype shutter systems or blade groups 14 and 16. Each systemor group comprises three shutter blades 14a, 14b, in the first group,16a, 16b, and 16c in the second group. In each case only one of theblades, namely 14a and 16a, has an edge 1411a and 16nd, respectively,which completely spans or sweeps completely across the width of theexposure aperture during the opening and closing movements of theblades. The other blades of each group serve merely as supplementary orcover blades for closing that part of the area of the exposure aperture10a which is not closed by the primary blade 14a or 16a, respectively,when the primary blade is in aperture obstructing position.

It should be understood that the blades operate somewhat like the bladesof a ladys collapsible fan. When they are fully collapsed, the blades ofeach set overlie each other, entirely in the annular space within thehousing, around the central exposure aperture 10a, the blades of thefirst group 14 lying to the right of the exposure aperture as seen inFIG. 3, and the blades of the second group 16 lying to the left of theaperture. This position shown in FIG. 3, with both blades in the annularspace, occurs only during the making of an exposure. Normally, in therest position, one group of blades is collapsed to lie within theannular space, and the other group of blades is extended or expanded soas to lie across the exposure aperture 10a and prevent passage of lighttherethrough.

Each blade has a control slot. The slots in the blades of the firstgroup or set are designated respectively at l4as, l4bs, and 140s, whilethose in the blades of the second group or set are designated at 16as,l6bs, and s. A control pin 18a on an operating lever 18 engages in thecontrol slots of the blades of the first group, and a similar controlpin 20a on a second control lever 20 engages in the slots of the bladesof the second group or set 16. The control pins 18a and 20a may also bereferred to as entraining means, since they entrain the baldes byengagement in the control slots of the blades, which slots may also becalled operating slots or operating means. As best seen in FIG. 2, thesecontrol levers l8 and 20 are mounted on separate pivots 18b and 20b inthe housing. Both levers, as shown, are curved so as not to obstruct theexposure aperture in any position of the lever, the pivot pin 18b or 20brespectively being near one end of its lever, and the control pin 18aand 20a, respectively, being substantially at the other end of thecontrol lever.

Both control levers are actuated by a driving element in the form of aring 22 extending circumferentially around the exposure aperture 10a androtatable concentrically therewith. The driving ring contains operatingmeans in the form of two actuating slots, 22a and 22aa in which arerespectively engaged an actuating pin 18c on the operating lever 18 andan actuating pin c on the operating lever 20. These pins constituteentraining means for operatively connecting the levers 18 and 20 to theoperating means 22a and 22aa of the driving element 22. Each of theactuating slots has a dwell portion concentric with the axis of rotationof the driving ring 22, and another or cam-rise portion which is obliqueor cam-like, having a radial component or rise as well as acircumferential component. When the respective actuating pin is in theconcentric or dwell portion of the actuating'slot, circumferentialmovement of the ring 22 will not move the resepective pin and thereforewill not cause any swinging movement of the respective operating lever18 or 20. But when the actuating pin is in the oblique or cam-riseportion of the actuating slot, rotation of the ring 22 will cause aswinging movement of the respective lever 18 or 20. This will causemovement of the resepctive control pin 18a or 20a, and the movement ofthis control pin will, in turn, cause the respective shutter blades 14or 16 to swing. The levers l8 and 20 thus constitute intermediate meansinterposed between the driving element 22 and the blade systems, foroperating the blade systems from the driving element. A thin interplate24 (FIG. 6) with a central opening corresponding to the exposureaperture 10a is interposed between the two blade systems 14 and 16, toinsure that the blades of one group do not interfere with the blades ofthe other group when they perform their swinging movements. The blades14 are located in front of the plate 24, and the blade 16 behind theplate 24, between it and the driving ring 22.

The driving ring 22 is operated by a main driving member or mastermember 26 rotatably mounted on the forward end 30a of a tensioning orcocking spindle 30 which extends out through the back wall of theshutter housing and into the associated camera (not shown) so as to beoperated by mechanism within the camera. The driving member 26 has aneccentric driving pin 26a engaging in a driving slot 22b formed radiallyin the driving ring 22. The pin 26a thus acts as a next half revolution(the driving member 26 always turning in the same counterclockwisedirection) the pin 26a will turn the ring 22 back from its extremecounterclockwise position of FIG. 4, to its extreme clockwise positionof FIGS. 1 and 2.

Two notches 26b and 26bb are arranged diametrically opposite each otheron the periphery of the driving member 26. A latch or trip lever 28(FIG. 5) pivotally mounted in the shutter housing, will engage in one oranother of these two notches and hold the driving member 26 in one orthe other of its two diametrically opposite positions, the latch beingspring biased toward latching position.

The main driving member or master member 26 is turned by means ofatensioning disk or cocking disk 34 which is mounted for limited axialmovement on the spindle 30 but is non-rotatably coupled thereto by meansof a spline 32 or its equivalent, so that the disk 34 must always turnwith the spindle 30 regardless of its slight axial movement on thespindle. The disk 34 has a chamfered pin 34a projecting forwardly fromthe front face of the disk, in position to engage in one or another ofthe two notches 26b and 26bb of the driving member 26. The disk also hasa pin 34b projecting rearwardly from the disk, and serving as an anchorfor one end 36a of the main driving spring or master spring 36, which iscoiled around the spindle 30. The other end 36b of the driving spring 36is engaged in an oblique setting slot 38a in the exposure time settingring or shutter speed setting ring 38 rotatable on the shutter housingand accessible for manual grasping. (See FIG. 6 as well as FIG. 5.)Because of the oblique nature of the slot 38a,

rotation of the setting ring 38 in one direction will serve to wind thespring 36 more tightly, to increase the speed of operation of theshutter, while rotation of the setting ring 38 in the opposite directionwill relax or slightly unwind the spring 36, resulting in sloweroperation of the shutter. The setting ring 38 is provided with the usualconventional shutter speed scale graduations, read in conjunction with asuitable index mark.

In addition to the main driving spring 36, there is also another spring(not shown) which urges the disk 34 axially toward the driving member26, to tend to keep the pin 34a on the driving disk engaged in one orthe other of the two notches 26b and 26bb. The rear end 30b of thespindle 30 projects out the rear of the shutter housing, as alreadymentioned, and is provided with a coupling slot 300 by which the spindleis coupled to conventional tensioning or cocking mechanism within thecamera body, which tensioning mechanism is preferably but notnecessarily coupled with the film winding or film transport mechanism ofthe camera, as quite customary.

When the tensioning mechanism of the camera is operated, this turns thespindle 30 clockwise through half a revolution. Assuming that, at thebeginning of the tensioning operation, the pin 34a was engaged in thenotch 26b, the commencement of clockwise rotation of the spindle 30 andthe disk 34 will cause the disk 34 to be displaced axially rearwardly onthe spindle, because of the camming action of the oblique or chamferedside of the pin 34a reacting against the side of the notch 26b in themember 26. The member 26 cannot turn at this time, because it is held bythe latch 28. At the completion of half a revolution in the clockwisedirection, the

pin 34a will have moved from the full line position shown in FIG. 5 tothe dotted line position shown in FIG. 5, where it will now be oppositethe other notch 26bb of the member 26, and it will snap into and seat inthis notch 26bb, under the influence of the axial spring abovementioned. The parts are now tensioned or cocked, and ready to drive themember 26 through half a revolution in the counterclockwise direction,when the latch 28 is released. The clockwise rotation of the spindle 30and disk 34 has served, of course, to tension or wind up the maindriving spring 36. At the conclusion of the tensioning movement, thetensioning or cocking lever on the camera is released and returns to itsinitial rest position in the usual manner, through a ratchet coupling,although the spindle 30 remains in its tensioned position.

With the driving member 26 in the position shown in FIGS. 1, 2, and 5,the shutter blades of the first group 14 will be extended or spread outfanwise, fully closing the exposure aperture a, as shown in FIG. 1, andthe blades of the second group or system 16 will be collapsed or closedup to lie over each other in the left hand side of the annular space inthe housing, as shown in FIG. 2, where they do not interfere withpassage of light through the exposure aperture. Before making theexposure, the shutter speed setting ring 38 is adjusted to the desiredposition (either before or after performing the tensioning or cockingoperation) and the parts are now ready for the exposure.

The exposure is initiated by operating the trip or release lever 28, towithdraw the nose thereof from the notch 26b of the member 26. The maindriving member 26 thus begins to turn in a counterclockwise directionunder the action of the spring 36, which acts on the member 26 throughthe coupling constituted by the parts 34 and 34a. This running downmovement continues through half a revolution or 180, being limited tothis extent by a suitable abutment (not shown) in the camera, acting onthe tensioning spindle 30.

During the first phase (about 90) of the running down movement of themain driving member 26 in the counterclockwise direction, the crank pin26a thereon operates on the driving slot 22b of the driving ring 22 toturn this ring 22 counterclockwise through half of its range ofmovement, from the position shown in FIGS. 1 and 2 to the position shownin FIG. 3. During this movement, the concentric part of the driving slot22aa is engaged with the pin 200 of the operating lever 20, so that nomovement of this lever takes place, and the blades of the second groupor system 16 remain in the same collapsed position shown in FIG. 2.However, during this first half of movement of the driving ring 22 thepin 180 of the operating lever 18 has been in the oblique portion, asdistinguished from the concentric portion, of the driving slot 22a, andso this motion of the driving ring has caused the operating lever 18 toswing clockwise from the position shown in FIG. 2, thereby carrying thepin 18a thereof rightwardly from the position in FIGS. 1 and 2 to theposition shown in FIG. 3, so that the pin 18a operates on the slotsl4as, l4bs, and 14cs of the blade group 14, swinging all of the bladesof this group rightwardly to a collapsed position shown in FIG. 3,thereby opening the exposure aperture so that light may enter.

During the second phase (about of the running down movement of the maindriving member 26 in the counterclockwise direction, the crank pin 26a,still operating in the slot 22!), swings the driving ring 22 stillfurther in a counterclockwise direction, from the position shown in FIG.3 to the position shown in FIG. 4. The pin 180 of the operating lever 18now rides in the concentric portion of the slot 22a, so that no furthermovement of the operating lever 18 takes place during this second halfof the movement of the ring 22. But the pin 200 of the operating lever20 is now in the oblique portion, as distinguished from the concentricportion, of the slot 22aa, so that the operating lever 20 is swungclockwise or to the right from its previous position illustrated in FIG.2, and the pin 20a thereof operates on the slots 16as, 16bs, and s ofthe blades of the second group or system 16, to swing these blades fromthe collapsed position shown in FIGS. 2 and 3, to the unfolded orextended position shown in FIG. 4, extending across and closing theexposure aperture to terminate the exposure. At the conclusion of therunning down movement, the nose of the trip or release latch 28 nowrests in the second notch 26bb of the driving member 26, and the pin 34alikewise is in this notch 26bb.

The two driving slots 22a and 22aa of the driving ring 22 may be sodimensioned with respect to each other that there is a slight time lagafter completion of the opening movement of one set of shutter blades,before the other set begins to close, so that both sets remainsimultaneously in the open position shown in FIG. 3, during such timelag. The extent of this time lag, if any, will increase the length ofthe exposure time. A slight time lag is usually preferred. But ifdesired, the slots 22a and 22aa may be shaped and proportioned to giveno time lag whatever, the blades of the second group or system beginningto close just as the blades of the first group or system reach theirfully open position, or may even be designed to give what may be calleda negative time lag, whereby the blades of the second group begin toclose a little before the blades of the first group reach their fullyopen position. Such a negative time lag is usually not preferred, butmay be employed if the shutter is to be used for extremely rapidexposures of short duration.

At the end of the exposure cycle such as described above, it will beapparent that the crank pin 26a of the main driving member 26 will cometo rest in the position shown in FIG. 4. It is not necessary to returnthe parts to initial position, before making the next exposure. Theexposure can start from the position shown in FIG. 4 just as well asfrom the position shown in FIGS. 1 and 2. In other words, if the partscome to rest in the position shown in FIG. 4, the next tensioningmovement of the spindle 30 will move the pin 34a out of the notch 26bband will put it in the notch 26, and the main driving member 26 will nowbe ready for another running down movement through half a revolution.During this next exposure, the drive member 26 will turn in thecounterclockwise direction, just as before, but the blades of the groupor system 16 will now constitute the first or opening group of blades,while the blades of the system 14 will now constitute the second orclosing group or system. The drive ring 22 will turn in a clockwisedirection rather than a counterclockwise direction, during this nextexposure, but the movement will be continuous in this direction duringthe entire running down time of the exposure cycle. The ring will notchange direction during the progress of the cycle.

In this way, the two blade systems alternate their functions as openingand closing the systems. They do not perform any reverse movement duringany single exposure operation. The main driving member always moves inone direction of rotation from one extreme or limit position to theother extreme or limit position, and the same is true of the drivingring 22. Because of the elimination of any return movement or reversalof direction of motion during any single exposure operagular light inletaperture, as well as those with the con ventional circular aperture.

What is claimed is:

1. A photographic shutter comprising a structure having a lightaperture, two separate blade systems each having a plurality of bladesmovable relative to which constitutes the closing blades of the firstexposure serves as the opening blades of the next succeeding exposure.

2. A shutter as defined in claim 1, further characterized by thefeatures that the main driving member (26) is in the form of a crank andhas a crank pin (26a) which engages in a driving slot (22b) in saiddriving element (22).

3. A shutter as defined in claim 1, further characterized by thefeatures that said light aperture (10a) is substantially circular, andthat said driving element is in the form of a ring (22) mounted forrotation around I said aperture.

each other in fanwise arrangement, the blades of each system beingmounted so that they may be spread fanwise relative to each other toclose said aperture and may be collapsed relative to each other to anon-obstructing position relative to said aperture, a main drivingmember, a driving element driven by said main driving member, andintermediate means operatively interposed between said driving elementand said two blade systems for operating one of said blade systemsduring an earlier part of an operating movement of said element and foroperating the other of said blade systems during a later part of anoperating movement of said element,- characterized by the features that:

a. said intermediate means comprises two levers, one

for each blade system,

b. each lever is pivotally mounted near one end,

c. each lever has near its other end a first entraining means inengagement with operating means in the respective blades of itsassociated blade system,

d. each lever has at an intermediate point a second entraining means inengagement with operating means in said driving element,

e. the respective blades of one blade system being substantiallyduplicates of the respective blades of the other blade system butarranged reversely with respect thereto, and

f. said driving element moves symmetrically from a first extremeposition through a central position to a second extreme position duringone exposure cycle and in the opposite direction from the second extremeposition through the central position to the first extreme positionduring the next exposure cycle,

g. the two blade systems alternating their functions during successiveexposures, so that the blade system which constitutes the opening bladesof a first exposure serves as the closing blades of the next succeedingexposure and the blade system 4. A shutter as definedinclaim 1, furthercharac' terized by the features that each blade system comprises threeshutter blades mounted for pivotal movement about a common bearing pin(12), and that one of the blades (14a and 16a) of each system has anopening and closing edge (l4aa and l6aa) and the other blades of thesame system serve as protecting blades (14b, 14c, and 16b, 16c) coveringthat part of the light aperture which is not covered by the blade whichhas the opening and closing edge, when the respective blade system is inaperture-closing position.

5. A shutter as defined in claim 1, wherein the operating means in saiddriving element is in the form of a first and a second slot, each slothaving a dwell portion and a cam-rise portion, said portions being soarranged that during an early part of a single operating movement ofsaid driving elementin one direction from one limit position to anotherlimit position, the cam rise portion of a first slot will operate saidintermediate means to open the previously closed blades of a first bladesystem while the dwell portion of the other slot will control saidintermediate means to maintain the blades of the other blade system inopen condition, and during a later part of said single operatingmovement of said driving element, the dwell portion of said first slotwill control said intermediate means to maintain the blades of saidfirst blade system in open condition while the cam rise portion of theother slot will operate said intermediate meansto close the previouslyopen blades of the other blade system.

6. A shutter as defined in claim 1, wherein said main driving member isa rotary member turning always in the same direction and rotatingthrough one-half of a revolution during each exposure cycle, and whereinduring a first exposure cycle the half revolution of said main drivingmember moves said driving element in one direction from a first limitposition to a second limit position to cause said driving element toopen the blades of a first previously closed blade system and to closethe blades of a second previously open blade system, and during the nextexposure cycle the half revolution of said main driving member movessaid driving element in an opposite direction from its said second limitposition to its said first limit position to cause said driving elementto open the blades of said second blade system and to close the bladesof said first blade system.

7. A shutter as defined in claim 5, whereinsaid first entraining meanson each lever is a control pin; said operating means in the respectiveblades are slots with which the respective control pins are engaged; andsaid second entraining means on each lever is an operating ment.

TJNTTED STATES PATENT oTTTcE @ERHWQATTE @F QQRREQTWN Patent NO. 3.9 3s7?Dated 5s Inventor(s) Hugo Weiss It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

On the cover sheet insert [Y3] Assignee compur werk Geaellsohaft Knitbeschrankter Haftuhg 8c (20.,

Munchen, Germany a Signed and sealed this 19th day of December" 1972,

(SEAL) Attest:

EDWARD MQFLETCTER JR. ROBERT GOTTSCHALK Attesting; Gfficer Commissionerof Patents FORM PO-105O (10-69) USCOMM-DC 60375-5 69 fr U.S. GOVERNMENTPRINT] HG OFFICE 7 I969 0-355-33L TJNTTTE STATES PATENT oTTTsT@ERZTMMATE @T RREUHN Patent No. 33 3977 Dated August 59 597 Inventor(s)Hugo WiSS It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet insert [7'3] Assignee compur-werk Gesellschaft mitbescfnrankter Hafwng 8c 60.,

Munchen, Germany 0 I Signed and sealed this 191th day of Deoember i972(SEAL) T Attest:

EDWARD MQFLETCFEHJR, ROBERT GOTTSGHALK Arresting Officer Gommissioner ofPatents FORM PC4050 USCOMM-DC 60375-969 .5, GOVERNMENT PRINTING OFFICE 7I969 O355-334,

1. A photographic shutter comprising a structure having a light aperture, two separate blade systems each having a plurality of blades movable relative to each other in fanwise arrangement, the blades of each system being mounted so that they may be spread fanwise relative to each other to close said aperture and may be collapsed relative to each other to a non-obstructing position relative to said aperture, a main driving member, a driving element driven by said main driving member, and intermediate means operatively interposed between said driving element and said two blade systems for operating one of said blade systems during an earlier part of an operating movement of said element and for operating the other of said blade systems during a later part of an operating movement of said element, characterized by the features that: a. said intermediate means comprises two levers, one for each blade system, b. each lever is pivotally mounted near one end, c. each lever has near its other end a first entraining means in engagement with operating means in the respective blades of its associated blade system, d. each lever Has at an intermediate point a second entraining means in engagement with operating means in said driving element, e. the respective blades of one blade system being substantially duplicates of the respective blades of the other blade system but arranged reversely with respect thereto, and f. said driving element moves symmetrically from a first extreme position through a central position to a second extreme position during one exposure cycle and in the opposite direction from the second extreme position through the central position to the first extreme position during the next exposure cycle, g. the two blade systems alternating their functions during successive exposures, so that the blade system which constitutes the opening blades of a first exposure serves as the closing blades of the next succeeding exposure and the blade system which constitutes the closing blades of the first exposure serves as the opening blades of the next succeeding exposure.
 2. A shutter as defined in claim 1, further characterized by the features that the main driving member (26) is in the form of a crank and has a crank pin (26a) which engages in a driving slot (22b) in said driving element (22).
 3. A shutter as defined in claim 1, further characterized by the features that said light aperture (10a) is substantially circular, and that said driving element is in the form of a ring (22) mounted for rotation around said aperture.
 4. A shutter as defined in claim 1, further characterized by the features that each blade system comprises three shutter blades mounted for pivotal movement about a common bearing pin (12), and that one of the blades (14a and 16a) of each system has an opening and closing edge (14aa and 16aa) and the other blades of the same system serve as protecting blades (14b, 14c, and 16b, 16c) covering that part of the light aperture which is not covered by the blade which has the opening and closing edge, when the respective blade system is in aperture-closing position.
 5. A shutter as defined in claim 1, wherein the operating means in said driving element is in the form of a first and a second slot, each slot having a dwell portion and a cam-rise portion, said portions being so arranged that during an early part of a single operating movement of said driving element in one direction from one limit position to another limit position, the cam rise portion of a first slot will operate said intermediate means to open the previously closed blades of a first blade system while the dwell portion of the other slot will control said intermediate means to maintain the blades of the other blade system in open condition, and during a later part of said single operating movement of said driving element, the dwell portion of said first slot will control said intermediate means to maintain the blades of said first blade system in open condition while the cam rise portion of the other slot will operate said intermediate means to close the previously open blades of the other blade system.
 6. A shutter as defined in claim 1, wherein said main driving member is a rotary member turning always in the same direction and rotating through one-half of a revolution during each exposure cycle, and wherein during a first exposure cycle the half revolution of said main driving member moves said driving element in one direction from a first limit position to a second limit position to cause said driving element to open the blades of a first previously closed blade system and to close the blades of a second previously open blade system, and during the next exposure cycle the half revolution of said main driving member moves said driving element in an opposite direction from its said second limit position to its said first limit position to cause said driving element to open the blades of said second blade system and to close the blades of said first blade system.
 7. A shutter as defined in claim 5, wherein said first entraining means on each lever is a control pin; said operatinG means in the respective blades are slots with which the respective control pins are engaged; and said second entraining means on each lever is an operating pin engaging the coordinated slot in said driving element. 